WTSP-A40 AC Surge Protective Device SPD for 230V Distribution Boards
The WTSP-A40 protects a 220/230V single-phase distribution board from switching and lightning transients. It clips to a 35mm DIN rail next to the breakers, takes the line and neutral through two poles and diverts the surge to earth within nanoseconds of the wavefront.
What 20kA and 40kA Mean on Site
The nominal discharge current In of 20kA is the 8/20µs impulse the device is tested to survive twenty times, and the maximum discharge current Imax of 40kA is the larger single hit it takes before the cartridge is spent. Sizing starts from the exposure of the building, so a board fed by an overhead line needs the full 40kA more than a board fed from an underground cable.
Clamping at 2kV
Residual voltage is held at or below 2.0kV at the rated current and the response time is under 25ns, so the let-through voltage reaching the load stays low for 230V appliances. A short and direct lead to the earth bar keeps that figure down, which is why the recommended conductor is larger than the minimum the terminals accept.
Wiring a Two-Pole Device
Line goes to L1, neutral to N, and the earth stud at the base goes to the panel earth bar on the shortest possible lead. The terminals take 35mm² solid or stranded copper, and 16mm² solid or 25mm² stranded is the recommended size. Because both poles sit in one body, the device takes two module positions on a 35mm rail.
Status Window and Housing
A window on each pole shows whether the cartridge is still doing its job, and a spent cartridge is replaced without taking the base off the rail. The housing is burning-proof nylon rated for -40°C to +85°C, which covers outdoor cabinets in most climates. Send your board voltage, system earthing and quantity to WTAIELE for a quote.
